tuyentran4992 · Oct 16, 2026
diff --git a/src/habit_hooks/initialise.py b/src/habit_hooks/initialise.py
@@ -18,6 +18,10 @@
 
 LANGUAGE_AGNOSTIC_PLUGIN = "generic"
 
+DEPENDENCY_DIRECTORIES = frozenset(
+    {"node_modules", "vendor", "site-packages", ".venv", "venv"}
+)
+
 
 @frozen
 class Plan:
@@ -42,8 +46,16 @@ def installs(self) -> tuple[str, ...]:
         )
 
 
+def _inside_dependency_directory(path: str) -> bool:
+    return any(part in DEPENDENCY_DIRECTORIES for part in path.split("/")[:-1])
+
+
 def plan(project_dir: Path) -> Plan:
-    files = git_listing.project_files(project_dir)
+    files = [
+        path
+        for path in git_listing.project_files(project_dir)
+        if not _inside_dependency_directory(path)
+    ]
     languages = tuple(used_languages(project_dir, files))
     config = _project_config(project_dir)
     plugins = _plugins(languages, config)

diff --git a/tests/test_init_names_no_language_from_dependency_directories.py b/tests/test_init_names_no_language_from_dependency_directories.py
@@ -0,0 +1,84 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from git_repo import git
+from habit_hooks.initialise import plan
+
+
+def _tracking(project_dir: Path, files: dict[str, str]) -> None:
+    git(project_dir, "init", "-q", "-b", "main", ".")
+    for relative, body in files.items():
+        path = project_dir / relative
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text(body, encoding="utf-8")
+    git(project_dir, "add", "-A")
+
+
+def test_a_php_file_inside_node_modules_names_no_language(init_project: Path) -> None:
+    _tracking(
+        init_project, {"node_modules/legacy-lib/index.php": "<?php echo 'legacy';\n"}
+    )
+
+    planned = plan(init_project)
+
+    assert planned.languages == ()
+    assert planned.plugins == ("generic",)
+
+
+def test_a_typescript_file_in_a_nested_node_modules_names_no_language(
+    init_project: Path,
+) -> None:
+    _tracking(
+        init_project, {"packages/app/node_modules/x/index.ts": "export const x = 1;\n"}
+    )
+
+    assert plan(init_project).languages == ()
+
+
+def test_a_python_file_inside_site_packages_names_no_language(
+    init_project: Path,
+) -> None:
+    _tracking(init_project, {"site-packages/foo/mod.py": "x = 1\n"})
+
+    assert plan(init_project).languages == ()
+
+
+def test_a_php_file_inside_vendor_names_no_language(init_project: Path) -> None:
+    _tracking(init_project, {"vendor/legacy/index.php": "<?php echo 'legacy';\n"})
+
+    assert plan(init_project).languages == ()
+
+
+def test_a_python_file_under_venv_names_no_language(init_project: Path) -> None:
+    _tracking(init_project, {"venv/lib/python3.12/site-packages/dep.py": "x = 1\n"})
+
+    assert plan(init_project).languages == ()
+
+
+def test_a_python_file_under_dot_venv_names_no_language(init_project: Path) -> None:
+    _tracking(init_project, {".venv/lib/dep.py": "x = 1\n"})
+
+    assert plan(init_project).languages == ()
+
+
+def test_real_php_source_still_names_php(init_project: Path) -> None:
+    _tracking(init_project, {"src/app.php": "<?php echo 'app';\n"})
+
+    assert plan(init_project).languages == ("php",)
+
+
+def test_a_file_named_like_a_dependency_directory_still_names_its_language(
+    init_project: Path,
+) -> None:
+    _tracking(init_project, {"src/vendorize.py": "x = 1\n"})
+
+    assert plan(init_project).languages == ("python",)
+
+
+def test_a_project_without_dependency_directories_is_unchanged(
+    init_project: Path,
+) -> None:
+    _tracking(init_project, {"src/app.py": "x = 1\n", "README.md": "# demo\n"})
+
+    assert plan(init_project).languages == ("python",)